I’m not sure of the proper nomenclature to describe my question, so let me just jump into an example. Let’s say that we’re modeling a scenario where:
- A Vendor can have multiple Customers
- A Vendor can have multiple Employees
- An Employee may only do work for one of the Vendor’s Customers
- An Employee’s only relationship with a Customer is via the Vendor
For simplicity, let’s ignore the myriad other real-world employment scenarios, and just say that there are contractual reasons for those last two constraints (e.g. protect intellectual property, non-compete).
Based on my meager UML skills, I’d be inclined to model these relationships as shown in the diagram below, which I believe is incorrect:
Specifically, I think that this diagram allows for an Employee to do work for many of the Customers, which violates the third constraint listed above. My question is:
- What is the proper way to depict the constraint that an Employee may only be associated with one of the Customers?
Thank you in advance for your help.